To read the original full thread and post questions/comments on this topic, please go to https://www.fjcruiserforums.com/forum...step-step.html
I wanted to run an external GPS antenna without any exposed wires or drilling. I purchased the Garmin GA25MCX antenna and got busy. First step is to remove the inside and outside A-Pillars as well as the driver’s side a/c vent. To remove the a/c vent just pull it straight towards you. If you take on this project you will break the Outside A-Pillar clips. My dealer had to order them, so if you are going to do this just go get the clips now. Part number 75392-35201. There are five of them but if you use my method of install for the antenna you will only need four because you are going to run the antenna in one of the clip holes. You will run it throught the center one towards the rear, which is only a couple of inches from the bolted retainer so the cover will remain tight without the 5th clip.
I did not use a tool to pry the Exterior cover, being the manly man that I am and not wanting to scratch anything, I just grabbed it with my fingers after removing the one retaining nut and pulled it off. Instructions for removal of the outside A- pillar cover can be found here:
A tip to avoid dropping the retaining nut into the abyss. The above instructions suggest that you use a magnet. I think it would be possible to drop the nut even with a magnet. Here is what I did. I had a piece of fuel line hose about six inches long. I used my Dremel tool to hollow out the inside just large enough to tightly hold a 10mm nut. After completely un-bolting the nut with a deep socket, I shoved the fuel line hose over the nut and gently pulled it out.
Once the A-Pillar covers and vents have been removed you will need to position the antenna in the center of the FJ about where you want it installed. It has a magnetic base which is good for holding it in place while you are getting everything positioned. I wanted a permanent install so I used automotive grade double sided tape to attach it to the vehicle but that was the last step, right now we just want to run the cable.
The cable will tuck under the trim piece above the windshield. There is a rubber gasket that you can carefully slip the cable by, I used a credit card to push past the rubber gasket. Run the cable under the trim piece and over to the A-Pillar. I had some foam tape to position the cable where I wanted it on the A-Pillar. Slip a rubber grommet on the cable and fish the cable through the center rear most clip hole. You have to fish the cable down and out of the A-Pillar nut hole and them back up through an un used hole on the inside of the A-Pillar on the interior side of the vehicle. It takes some time but I think it is worth it. I sealed the hole that I ran the cable in with silicone just in case. Make sure the wire runs forward in the void of the A-pillar cover so as not to crush it when everything is reassembled.
This is the void the antenna wire will sit in. Make sure that you don't put a clip back in this hole.
Fish the wire through the big hole first and then back up through the small un used hole on the interior side of the A-Pillar. It is a two step process to get the wire up through the exit hole. You have to run the wire down and then back up, there is a metal divider in the pillar that will not let you take a direct route.
Then drill a hole in the back of the docking station to run the antenna wire inside to the GPS. You can run it through the same hole as the power but it was a little crowded for me. I also put a grommet here. Neatly secure the wire to the factory wire harness that runs down the A-Pillar. This is where I took up the slack in the wire also. I wrapped the slack into 2 loops and then used wire ties to secure it to the factory harness which you can see in the picture above.
This is the back of the docking station. If you drill a hole like this for the antenna wire, make sure you drill it up high so that you do not make contact when you close the unit.
Then reassemble. As you can see the results are worth it. This was my reception and it was a very cloudy day and there were houses and trees all around me.
Edit: A couple of observations after driving around a few days with the external antenna: I have not lost reception since installing the antenna. Another thing that I noticed is that before installation of the antenna, maps would sometimes draw slowly and at times there would be blank sections in the top portion of the screen. This no longer happens and the only explanation that I have is that possibly the cpu is not consumed with finding satellites and is freed up to draw maps on the screen. Just a guess on my part but one thing is for sure, it works much better. Well worth the $30 and an hour or so of install time. (longer if you are anal about it and drinking beer as you go)